Color formation inhibition for storing ethylthioethanol in iron containing vessels

ABSTRACT

Amines, e. g., monoethanolamine and diisopropanolamine have been found to stabilize color formation when ethylthioethanol is stored in iron containing vessels such as carbon steel tanks or drums. The action of the inhibitor is specific for the compound ethylthioethanol.

[I We mes Me? [191 [111 3,73,339 Warner May 1, 1973 [54] COLOR FORMATION INHIBITION FOR STORING ETHYLTHIOETHANOL IN Primary Examiner-Lewis Gotts IRON CONTAINING VESSELS Assistant Examiner-D. R. Phillips [75] Inventor: Paul F. Warner, Bartlesville, Okla. Att0mey Young and Qmgg [73] Assignee: Phillips Petroleum Company, 57 ABSTRACT Bartlesville, Okla.

Ammes, e. g., monoethanolamme and [22] Filed: Oct. 8, 1970 diisopropanolamine have been found to stabilize color [21] AppL No: 79 326 formation when ethylthioethanol is stored in iron containing vessels such as carbon steel tanks or drums.

[52] US. Cl ..206/84, 252/401, 260/609 A h action of the inhibitor is Specific for the [51 Int. Cl ..B65b 29/00, C07C 149/02 pound ethylthioethanoli [58] Field Of Search ..260/609 A, 609 C;

252/401; 206/84 5 Claims, No Drawings COLOR FORMATION INHIBITION FOR STORING ETHYLTI-IIOETHANOL IN IRON CONTAINING VESSELS This invention relates to the inhibition of color formation when ethylthioethanol is stored in iron containing vessels, for example, carbon steel drums or tanks. It

also relates to an amine inhibitor for the prevention of chemical reaction in an iron containing vessel, for example, a carbon steel drum or tank, which contains ethylthioethanol. Further, the invention relates to a package containing in an iron containing vessel ethylthioethanol and an amine inhibitor.

In one of its concepts the invention provides a method for stabilizing ethylthioethanol against color deterioration or discoloration when it is stored in an iron containing vessel or tank, for example, in a carbon steel drum or tank by adding a minor quantity of an amine, e.g., monoethanolamine or diisopropanolamine to the container in which the ethylthioethanol is to be stored. In another of its concepts, the invention provides an ethylthioethanol stabilized against discolorasuch as a steel container or steel wool and the like by having as an additive in the ethylthioethanol an amine as herein described.

It has been found that ethylthioethanol stored in glass or aluminum does not develop a color. However, when ethylthioethanol is stored in carbon steel, brass and copper, it develops color on prolonged storage. The depth of color correlates well with the metal content of the ethylthioethanol, particularly the iron content thereof.

I have now found that addition of as little as 0.05 to 0.1 weight per cent monoethanolamine or diisopropanolamine to the ethylthioethanol greatly improves the color stability for storage when in'contact with carbon steel or other iron containing materials.

An uninhibited sample of ethylthioethanol which was stored for four months in glass and sunlight with a wad of steel wool present went from Gardner 1 to Gardner 18. However, samples of the same ethylthioethanol when inhibited with 0.05 weight per cent monoethanolamine and the other with 0.05 weight per cent diisopropanolamine, stored in identical fashion on the Gardner scale went from 1 to 2 in color.

It is an object of this invention to stabilize ethylthioethanol against discoloration. It is another object of this invention to provide a stabilizer for ethylthioethanol. It is a still further object of this invention to provide a substance which will stabilize ethylthioethanol against discoloration when it is in presence of an iron containing substance, for example, as it may be stored for prolonged periods in a carbon steel drum or tank.

Other aspects, concepts, objects and several advantages of this invention are apparent from a study of this disclosure and the claims.

According to the present invention, ethylthioethanol is stabilized against discoloration as it may be stored in the presence of an iron containing material such as a carbon steel tank or drum, steel wool and the like, which comprises adding, so that it will be present during the storage period, an amine, e.g., monoethanolamine or diisopropanolamine or a mixture of these amines to the ethylthioethanol prior to storing the same.

, tion due to presence of an iron containing material The following examples further illustrate the invention.

EXAMPLE I Tests on Ethylthioethanol with 0.112 Wt Water, in Presence of Steel Wool, Loosely Capped, Stored in Sunlight.

Gardner Color Inhibitor 0.10% 0.10% Days Storage None MEA DlPA 0 l l l 35 5 l 1 42 13 l l 84 18 2 2 l94 l8 5 5 EXAMPLE II Tests on n-Octylthioethanol with 0.63 Wt Water, in Presence of Steel Wool, Loosely Capped, in Sunlight.

Gardner Color Inhibitor Concentration, Wt MEA DIPA Days Storage None 0.05 0.10 0.05 0.10 0- 2 2 2 2 2 42 2 6 7 4 4 l 52 9 l 8 l 8 l 8+ 16 Generally, the ranges for the inhibitor content will be usually from about 0.005 to about 5 weight per cent, more preferably 0.01 to 0.5 weight per cent of inhibitor based upon the ethylthioethanol to be stored.

As can be seen by comparison of the examples, the action of the monoethanolamine and the diisopropanolamine, i.e., the amine stabilizers to which this invention relates appears to be quite specific in that the ethylthioethanol discoloration was substantially prevented or inhibited whereas discoloration of the n- Octylthioethanol was not inhibited.

When testing Z-Mercaptoethanol in manner similar to the testing of ethylthioethanol for color stability employing an amine as herein described, the Z-Mercaptoethanol went off color almost immediately.

The stabilization of sulfur compounds generally and particularly to prevent discoloration during prolonged periods of storage is an important problem in the art. Accordingly, it appears there has been here set forth a group of stabilizers which can be used effectively to stabilize ethylthioethanol which as it has developed is stabilized albeit other sulfur compounds as noted are not stabilized.

Reasonable variation and modification are possible within the scope of the foregoing disclosure and the appended claims to the invention the essence of which is that ethylthioethanol has been found to be stabilized against discoloration upon prolonged storage by using a minor quantity of an amine, e.g., monoethanolamine and/or diisopropanolamine.

I claim:

1. A stabilized ethylthioethanol in presence of an iron containing material such as a carbon steel tank or drum or steel wool which comprises a stabilizer selected from monoethanolamine, diisopropanolamine and mixtures thereof.

2. A stabilized ethylthioethanol stored in presence of an iron containing material such as a carbon steel tank or drum or steel wool, said ethylthioethanol containing a stabilizer selected from monoethanolamine and therein ethylthioethanol and as a stabilizer therefor an amine which is selected from monoethanolamine and diisopropanolamine and mixtures thereof.

5. A package according to claim 4 wherein the amine is present in an amount in the range of from about 0.005 to about 5 weight per cent. 

2. A stabilized ethylthioethanol stored in presence of an iron containing material such as a carbon steel tank or drum or steel wool, said ethylthioethanol containing a stabilizer selected from monoethanolamine and diisopropanolamine and mixtures thereof in an amount in the range of about 0.005 to about 5 weight per cent.
 3. A stabilized ethylthioethanol containing from about 0.005 to about 5 weight per cent of an inhibitor according to claim
 1. 4. A package comprising an iron containing vessel, for example, a carbon steel storage container having therein ethylthioethanol and as a stabilizer therefor an amine which is selected from monoethanolamine and diisopropanolamine and mixtures thereof.
 5. A package according to claim 4 wherein the amine is present in an amount in the range of from about 0.005 to about 5 weight per cent. 